diff --git a/notes/sections/1.md b/notes/sections/1.md
index 8667d41..dd5949b 100644
--- a/notes/sections/1.md
+++ b/notes/sections/1.md
@@ -20,7 +20,7 @@ an histogram and plotted with matplotlib. The result is shown in @fig:landau.
 
 ![Example of N points generated with the `gsl_ran_landau()`
 function and plotted in a 100-bins histogram ranging from -10 to
-80.](images/landau.png){#fig:landau}
+80.](images/landau.pdf){#fig:landau}
 
 
 ## Randomness testing of the generated sample